Grand Theft Auto Vice City Walkthrough :
Fire Truck Missions

The Fire Truck missions are REALLY easy, and if you do 20 on each island you get a flamethrower. They don't have to be sequential.

Really, the fire truck is a great way to "find" all sorts of cars. Special cars often can't be found anywhere on the map, but if you keep doing fire truck missions, you'll come across one on fire. Just put it out and take it!.